Using data, create a mathematical model (based on the number of years) that you can use to predict the population in 2019?

Question

The population of a city, with land area 36 square miles and 109 parks has been decreasing over time. In 2010 the population was 5,900. In 2012 the population had dropped to 4,700. By 2014 the population was 3,500 and by 2015, 2900. 

a) Using this date, create a mathematical model (based on the number of years) that you can use to predict the population in 2019? [P for population x for years]

Answer 1

If you use the Linest function is Excel, you can get a polynomial formula that fits the existing data very well.

It is Population = (-2.24946x10^-15)*year² -600*year +1211900.

The year is inserted as 2010, 2015 etc.

When you insert year 2019, you get 500.

The problem did not specify the type of math expression to predict (exponential, power, logarithm etc)

You can get this equation manually by assuming a polynomial of order n and solving n equations to get the coefficients but using Excel does that for you!

Note.... whenever you estimate beyond the data set, you are extrapolating!